DP CRCs don't really work on g4x. If you want any CRCs on DP you must select the CRC source before the port is enabled, otherwise the CRC source select bits simply ignore any writes to them. And once the port is enabled we mustn't change the CRC source select until the port is disabled. That almost works, but not quite :( Eventually the CRC source select bits get permanently stuck one way or the other, and after that a reboot (or possibly a display reset) is needed to get working CRCs on that pipe (not matter which CRC source we try to use). Additionally the DFT scrambler reset bits we're trying to use don't seem to exist on g4x. There are some potentially relevant looking bits in the pipe registers, but when I tried it I got stable looking CRCs without setting any bits for this. If there is a way to make DP CRCs work reliably on g4x, I wasn't able to find it. So let's just remove the broken code we have. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190214192219.3858-3-ville.syrjala@linux.intel.com Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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